Vanadium recovery from acidic solutions

ABSTRACT

A method for the extraction of vanadium (V) from acidic mixtures containing fluoride comprising effecting the extraction with amines in a water-immiscible organic solvent, the vanadium being complexed with the extractant and being extracted into the organic phase.

tates Lucid et al.

[ 1 May 22,1973

[54] VANADIUM RECOVERY FROM ACIDIC SOLUTIONS [73] Assignee: Kerr-McGeeCorporation,

Oklahoma City, Okla.

[22] Filed: Sept. 4, 1970 [21] App1. No.: 69,938

[52] 11.8. C1. ..23/312 ME, 423/63, 23/312 P [51] Int. Cl. ..B01d 11/04,C01g 31/00 [58] Field of Search ..23/312 ME, 309, 312 A,

23/312 P, 165 C, 19.1 V; 423/63 [56] References Cited UNITED STATESPATENTS 3,206,277 9/1965 Burwell ..23/312 ME 3,367,749 2/1968Koerner.... ..23/312 P 3,131,993 5/1964 Gustison 23/321 ME 3,348,90610/1967 Henrickson 23/312 ME 3,437,454 4/1969 Shaw 23/312 MB 3,206,2769/1965 Burwell 23/312 ME 2,859,094 11/1958 Schmitt ..23/312 ME 2,937,9255/1960 Blake ..23/3l2 ME 2,864,668 12/1958 Ba1dwin..... 23/312 ME2,812,233 11/1957 Lewis 23/312 ME 3,223,476 12/1965 Hart ..23/14 5FOREIGN PATENTS OR APPLICATIONS 245,763 7/1963 Australia ..23/ 19.170,866 1/1970 East Germany 23/19.4

OTHER PUBLICATIONS Green, Metallurgia, Vol. 70, No. 422, Dec., 1964,pages 299-302.

Nuclear Science Abstracts, Vol. 20, No. 11, June 15, 1966, pages2277-2278, No. 18561.

Nuclear Science Abstracts, Vol. 10, No. 18A, Sept. 10, 1956, page 905,No. 7573.

Nuclear Science Abstracts, Vol. 11, No. 4 Supp., Feb. 28, 1957, pages253-254 No. 2356.

Ishimori, Nippon Genshiryokii Gakkaisha, Vol. 4, No. 2,1962, pp. 117thru 125.

Coleman, Proc. of International Conf. on Peaceful Uses of At. Energy,V01. 28, 1958, pp. 278 to 288.

Primary Examiner-Norman Yudkoff Assistant ExaminerS. J. EmeryAttorney-William G. Addison [57] ABSTRACT A method for the extraction ofvanadium (V) from acidic mixtures containing fluoride comprisingeffecting the extraction with amines in a water-immiscible organicsolvent, the vanadium being complexed with the extractant and beingextracted into the organic phase.

4 Claims, No Drawings VANADIUM RECOVERY FROM ACIDIC SOLUTIONS BACKGROUNDOF THE INVENTION Phosphoric acid is generally produced commercially byone of two methods. One method is generally called the furnace method,and the other is generally referred to as the wet process" method. Inthe wet process method of producing phosphoric acid, phosphate rock iscontacted with a mineral acid such as sulfuric acid. Most phosphate rockcontains metal compounds in varying amounts. In many cases these metalcompounds are dissolved from the phosphate rock and appear in the wetprocess acid as contaminants. Vanadium compounds are among thosedissolved from the phosphate rock, particularly when the rock is fromthe so-called Western phosphate deposits of Idaho, Wyoming, Utah andMontana.

Vanadium is an undesirable component of wet process phosphoric acid inthat it prevents the use of the phosphoric acid in making animal feedsupplements, as the amount of vanadium must be kept at a low level insuch animal feed supplements.

On the other hand, vanadium itself is a valuable material and wetprocess phosphoric acid can be an important source of this material.Therefore, a process for the recovery of vanadium from wet processphosphoric acid provides an important benefit, in that the vanadium isconverted from an undesirable contaminant to a valuable by-product.

Heretofore, attempts have been made to recover vanadium from wet processphosphoric acid. One involves addition of a soluble ferrocyanidecompound to the acid to precipitate the vanadium, as described morefully in U.S. Pat. No. 1,544,911. Other such processes involveextraction of the acid with an organic extractant for the vanadium. U.S.Pat. No. 2,211,119 describes a process in which the preferred organicextractant is isopropyl ether. U.S. Pat. No. 3,437,454 describes aprocess in which the preferred organic extractant is an alpha-hydroxyoxime.

Other commercial process streams which contain vanadium exist. Forinstance, leaching of uranium ores with sulfuric acid frequently resultsin solutions containing vanadium, uranium, and iron. Another source ofvanadium is ferrophosphorus, a by-product from electric furnaceproduction of elemental phosphorus. Ferrophosphorus is roasted usuallywith salt or limestone and leached with water or acid. Furtherprocessing of these solutions by precipitation usually leaves low gradevanadium solutions which are sometimes processed by solvent extraction.

Amines and ammonium salts have been used for the recovery of thesevanadium values from acidic solutions. However, below pH 1.3, vanadiumis not extracted in significant amounts and residual vanadium frequentlyis left in the aqueous rafiinate even at a higher pH.

Accordingly, improved processes are the effort of much research torecover vanadium from commercial sources under favorable conditions andin improved yields.

SUMMARY OF THE INVENTION In accordance with this invention, it has beendiscovered that vanadium can be recovered from wet process phosphoricacid by extraction of the acid at a pH of from about 0.0 to about 1.5using an organic extractant comprising a hydrocarbon solvent and atleast one amine. The vanadium values are extracted from the acid intothe organic phase, and the loaded organic phase can then easily beseparated from the wet process acid due to the immiscibility of the acidand the organic phase. The vanadium values can then be recovered fromthe organic phase, as for example by stripping with a suitable strippingsolution such as a 10 percent solution of sodium carbonate. The vanadiummay be precipitated from the stripping solution by conventional priorart methods.

In accordance with another aspect of the present invention, it has beendiscovered that if phosphine oxides are combined with the extractantsdescribed above, the combination is effective to extract vanadium (V)from acidic solutions other than wet process phosphoric acid. Further,if fluoride is present in such solutions, the combination is aneffective extractant even if the solution has a low pH, for example,about 0.0 to 1.5.

Examples of suitable primary amines include a mixture of C-l8 to C-22aliphatic primary amines. Aliphatic amines corresponding to such amixture include Primene JMT (Rohm & I-Iaas Co.). One of the preferredamines of this mixture which may also be used alone is a C-20 primaryalkylamine of the formula Also illustrative of suitable primary aminesis a mixture of C-12 to C-14 primary alkylamines. A commerciallyavailable mixture of such amines is Primene 8 l-R (Rohm & Haas Co.). Atypical amine of this mixture is the C-l2 alkylamine of the formulaExamples of suitable secondary amines include bis( 1-isobutyl-3,S-dimethyl-hexyl) amines, and mixtures ofN-dodecenyl(trialkylmethyl) amines and mixtures of N-lauryl(trialkylmethyl) amines. Examples of mixtures of N-dodecenyl(trialkylmethyl) amines are those which are a C-12 to C-15 homologousmixture such as Amberlite LA-l (Rohm & Haas Co.). An amine of thismixture which also may be used alone has the formula Mixtures ofN-lauryl(trialkylmethyl) amines include homologous mixtures of C12 toC-15 amines such as Amberlite LA-l (Rohm & Haas Co.). A typical amine ofthis mixture has the formula Examples of suitable tertiary aminesinclude tricaprylyl amine, trilauryl amine, triisooctyl amine,tritridecyl amine and mixtures of tertiary amines, such as a mixture ofC-8, C-10 and C-l2 tertiary alkyl amines commercially available asAdogen 368" (Ashland Chemi cal Co.). 1

Examples of suitable quaternary amines are tricaprylylmethyl ammoniumchloride and tritridecylmethyl ammonium chloride.

Examples of alkyl phosphine oxides include tri-noctylphosphine oxide,tri-n-decylphosphine oxide and tris-( 2-ethylhexyl) phosphine oxide.

Other modifiers may optionally be addedto the extractant mixture, suchas tributylphosphate, long chain aliphatic alcohols, and the like.

Generally, the total amount of the novel extractant will vary from about1 to 50 percent by weight based on the total weight of the organicphase. A preferred percentage range is from 2 to percent. The ratio ofthe organic phase to the acidic phase is not critical.

The term water-immiscible organic solvent as used herein refers to anorganic material normally liquid at ambient temperatures which issubstantially, but not necessarily entirely, insoluble in water. Thepreferred organic solvents for the process of the present invention arehydrocarbons. Examples of suitable hydrocarbon solvents includeisooctane, kerosene, Soltrol 170 (a commercially available naphthenichydrocarbon solvent), benzene, toluene, xylene, isodecane, fuel oils,mineral oils, hexane, heptane, octane, Panasols" (commercially availablepetroleum aromatic solvents), Napoleum 470 (commercially availablepetroleum naphtha), and the like. Solvents which contain functionalgroups can also be employed providing that the functional groups do notadversely affect the extraction. Thus, chlorinated and fluorinatedhydrocarbons such as carbon tetrachloride, trichloroethylene, andperfluorokerosene may be used.

It has been found in the practice of this invention that fluoride mustbe present in the wet process phosphoric acid in order for theextractants of the present invention to properly complex thevanadium(V). Although the exact theory of the complexing is not known,it is believed that the fluoride is complexed with the vanadium(V) andthe complexing agent.

The amount of fluoride present in the mixture preferably is about 0.25mole per mole of vanadium present although a large excess of fluoridedoes not harm the extraction.

Fluoride is a natural component of wet process phosphoric acid andtherefore wet process phosphoric acid is particularly suited for theextraction process of the present invention.

With respect to the treatment of wet process phosphoric acid, thepresent invention comprises the treatment of the raw acid with anoxidizing agent prior to extraction, so that the vanadium is convertedto the pentavalent state. Without converting the vanadium to thepentavalent state, the extraction process with the complexing agents ofthe invention is not satisfactory, as vanadium in the lower oxidationstate does not form a complex with the extractants contemplated withinthe scope of the invention.

Amine It has been found that contact time between the organic extractantphase and the wet acid phase is an important variable to consider whenextracting vanadium from wet acid. Longer contact times result inincreased vanadium extraction. In practice, contact times of from about1 minute to are satisfactory with about 5 minutes to 30 minutes percontact being especially preferred at temperatures of from about 30 50C.

EXAMPLE I Commercial wet process phosphoric acid containing 1.6 g/l of V0 was oxidized with sodium chlorate to insure all of the vanadium was inthe pentavalent state. This solution was contacted for 10 minutes withequal volumes of the quaternary amine tricaprylylmonomethylarnmoniumchloride in Napoleum 470. The following table gives the percent vanadiumextracted as a function of amine concentration.

Amine (Molarity) V 0 extracted (96) Similar results were obtained usingprimary, secondary and tertiary amines.

EXAMPLE II Commercial wet process phosphoric acid was oxidized withsodium chlorate to raise the vanadium contained therein to thepentavalent state. Portions of this aqueous solution were contacted withequal volumes of organic extractant solutions for 2 minutes at ambienttemperature. The aqueous raffinate from each extraction was recontactedwith fresh organic solution and this procedure was repeated for a totalof six stages. Each organic solution contained 0.05 M amine 0.05 Mtri-n-octylphosphine oxide, 5 percent tributylphosphate in Napoleum 470.Primary, secondary, tertiary and quaternary amines were tested. Thefollowing table gives the vanadium analysis of the aqueous solutionsshowing a high level of vanadium extraction is attained.

Stage V105 (g./l.) (aqueous) 'Irlcaprylylamlnv 1.58 0.28 0.21 0.12 0.100.12 0.12 Trllaurylam1ne 1.57 0.40 0.22 Poor break time'Irllsoortylaminc 1.22 0.42 0.39 0.35 0.35 0.33 0.33 'Irltridccylamme1.57 0.58 0.31 0.22 0.16 0.16 0.16 'Irltrldecylmethyl ammonium chloride1.57 0. 23 Tricaprylylmethylammonlum chl0rlde 1.57 0.27 0.23 0.23 0.230.21 0. 21 Bis (1-lsobutyl-3,fi-dimethylhexyl)amine -1.57 0.65 0.43 0.270.21 0.21 0,20 N-dodecenyl(trlalkylmethyl)amine:trlalkylmethyl=homologous mixture, 12-15 carbon atoms. 1.57 0.540.40 0,20 029 0,29 0.23 N-lauryl (trlalkylmethyl) amino:trlalkylmethyl=homologous mixture, 12-15 carbon atoms ..1.57 0.56 0.430.38 0,24 0,10 0.17 Trialkylmethyl amine: homologous mixture, 18-22carbon atoms 1.57 0.27 0.27 0. 22 0.22 0. 22 0.22Trialkylmethylamlne:homologousmlxture Crz-Cu 0.47 0.34 0.31 0.28 0.270.26

In general, the extraction efficiency decreases as the temperature isincreased, although in some instances it may not be practical to operateat ambient temperature conditions.

EXAMPLE Ill An experiment with mixtures of tri-n-octylphosphine oxidewith the trialkyl amine tricaprylyl amine in one case and the thequaternary amine tricaprylylmonomeaqueous phase; removing the organicphase and recovthylammonium chloride in another case show the effectering the vanadium from the organic phase by treatof different amine tophosphine oxide ratios on extracment with an alkaline strippingsolution.

tion of vanadium from wet process phosphoric acid. 2. A process as setforth in claim lwherein said Organic composition (molar) Stage V205(g./l.) (aqueous) Tricaprylylammonium chloride TOPO Tricaprylyl amineWhat is claimed is:

acidic solution is wet process phosphoric acid.

1. A process which comprises extracting vanadium 3. A process as setforth in claim 1 in which the amine (V) from an aqueous acidic solutionhaving a pH of is selected from the group consisting of primary, secfromabout 0.0 to about 1.5 and containing fluoride in ondary, tertiary andquaternary amines. an amount of at least about 0.25 mole per mole of va-4. A process as set forth in claim 1 wherein said fluo ride is presentin said acidic solution in an amount of about 0.25 mole per mole ofvanadium.

nadium by contacting said solution with an organic phase containing asthe extractant at least one aliphatic amine in a hydrocarbon solventtherefor to form an organic phase containing the vanadium separate froman

2. A process as set forth in claim 1 wherein said acidic solution is wetprocess phosphoric acid.
 3. A process as set forth in claim 1 in whichthe amine is selected from the group consisting of primary, secondary,tertiary and quaternary amines.
 4. A process as set forth in claim 1wherein said fluoride is present in said acidic solution in an amount ofabout 0.25 mole per mole of vanadium.